Question

An object of mass 10 kg moves at a constant speed of 10 ms⁻¹. A constant force, that acts for 4 sec on the object, gives it a speed of 2 ms⁻¹ in opposite direction. The force acting on the object is(a) –3 N (b) –30 N(c) 3 N (d) 30 N

Answer 1

option a -3N... is the answer duce

Answer 2

Answer:

-3N

Explanation:

Mass of the object = 10kg (Given)

Speed = 10 ms⁻¹ (Given)

Speed after force = 2 ms⁻¹ (Given)

Time = 4 sec (Given)

After giving a speed of 2 m/s in opposite direction the net velocity becomes Change in velocity  = -2-10=-12

Time required = 4 seconds

Thus,  

a=Δv/t  = Final velocity/ Time taken

=-12/4

=-3 m/s²

Thus, the force acting on the object is –3 N